Electric arc-lamp.



No- 727,6 0. 'PATENTED MAY 12, 1903.

E.'W. RICE, JR. ELEOTRIG ARC LAMP. APPLICATION FILED AUG. 26, 1901.

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Witnesses I Inventor? I a sdwinwfiiceur i '1 I I Atty.

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No. $27,690. Patented May 12, 1903.

UNITED STATES PATENT OFFICE.

EDWIN WV. RICE, JR., OF SCHENECTADY, NEIV YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC ARC-LAM P.

SPECIFICATION forming part of Letters Patent No. 727,690, dated May 12, 1903. Applieation filed August 26,1901. sta n No. 73.214. int model.)

To all whom it may concern.- struck afresh. With an increase of voltage Be it known that I, EDWIN W. RICE, J12, a at the arc the arc-stream becomes more atcitizen ofthe United States, residing atSchentenuated and is consequently more difficult ectady, in the county of Schenectady, State to maintain unless a considerable steady- 5 of New York, have invented certain new and ing resistance is employed. I provide for a useful Improvements in Arc-Lamps, (Case quicker response ofthe regulating mechanism No. 1,724,) of which the following is a speciby using a short circuit for the regulatingfication. coil containing a variable resistance which The object of this invention is 'to provide is automatically adjusted to suit the current IO an arc-lamp for use on constant-potential cirflowing through the lamp. For this purpose cuitsin whicha longer are may be maintained I prel'er to employ a shunt-circuit including than with lamps as ordinarily constructed a carbon contact or contacts the resistanceof and a greater voltage drop across the arc with which is varied by a coil carrying the lampcurrents of small amperage, by which a wider current, and the latter is rendered extremely 15 zone of illumination is maintained and a sensitive by providing it with a very short smaller than common amount of steadying magnetic circuit of laminated structure by resistance required. which changes of magnetic density are ren- In modern inclosed-arc lamps a potential dered more rapid. Thus on a weakening drop of from seventy five to eighty volts current the tendency of the regulating-coil 7o 20 across the are on circuits of one hundred and to hang fire or'act sluggishly is corrected by an ten volts is maintained, itbeing found necesinstantaneous increase of carrying capacity sary with the regulating mechanism comof the shunt, which diverts current from the monly employed to insert an idle resistance regulatingmagnet, and therefore instantly in the arc-circuit to prevent rupture of the weakens it and permits the carbons to ap- 25 are. This is particularly the case withlamps proach. The controlling-coil for the resist-- operating under moderate currents, since the ance need not necessarily carry the entire fluctuations in current strength, due to irreglamp-current, but may be in shunt to the arc, ularities in the texture of the carbons, causes or it may even be the regulating-coil itself, the arc to go out frequently unless such a as will be hereinafter more fully described. 3o steadying resistance be employed. In the accompanying drawings, which illus- Itis the object of 'myinvention to construct trate the invention, Figures 1, 2, and 3 are the lamp so that it may be employed with a diagrams of several types of lamp by which small resistance in circuit and that a longer my. improvements may be carried out. are may be maintained with satisfactory In Fig. 1 is shown an arrangementin which 5 illumination. the regulating-coil 1 is shunted by a circuit The chief difficulty with arc-lamp mechanincluding carbon contacts 2 2 and, if deism as heretofore constructed is that the regusired, a small auxiliary resistance 3, the conlating mechanism is not sufficiently rapid in tacts being normally held together by a stifi action to keep the arc burning. There is spring 4, but adapted to be separated and 0 40 great inertia of the moving parts, both mehave the force of contact graduated bya magchanical and magnetic, which prevents a net 5 in series with the lamp. This magnet sufficiently prompt response of the core to should be provided with a short core, so as to the fluctuating current conditions. The dehave a short time constant, or, in other words, cline of currenton a hard spot in the carbon be very quick in magnetization and demag- 5 being encountered by the arc is instantanenetization, and is preferably given along airous, and before the regulating device can pergap with the same end in view and is also mit the approach of the carbons to compenlaminated to prevent the development of sate for the increased resistance of the arceddy-currents and retardation of demagnetistream the arc has been stretched to the snapzation. Adash-pot 6, resisting upward move- :00 5o ping-point and extinguished, whereupon the ment, is connected to the armature. The arcarbons fall into contact and the arc must be mature and connected parts are made as light as possible to reduce inertia. A resistance 7, sufficient to absorb a drop of about fifteen volts, is employed, 8 representing the tripping-floor of the clutch. Witha lamp as thus organized any variation in the conductivity of the arc-stream is accompanied by a corresponding variation in the pull of the magnet 5. Its armature being within grip of its field at all times is instantly responsive and weakens or increases the contact in the shunt, thereby varying the resistance of the shuntpath. For an increase of current this action is not so material; but for a decrease it is very important, since by reason of the construction of the magnet 5 it is much quicker to respond to a diminution of current than the regulating-coil 1, which has large magnetic and mechanical inertia; but when the shunt is lowered in resistance a largely-increased part of the lampcurrent is diverted from the coil 1, thereby greatly decreasing its power and permitting instant release of its core. Instead of placing the coil 5 in series With the lamp-current it may be placed in shunt to the are, as indicated in Fig. 2, the parts being so arranged that on an increase of voltage across the arc the resistance of the shunt will be decreased. The effect is here the same in character as that in Fig. l namely, with an increase of current, which means a decrease in the thickness of the arcstream and a consequent increase of arc-potential, more current flows in the controllingmagnet 5, therebyincreasing the conductivity of the shunt and causing a quicker release by the regulating-magnet 1 on its core.

The arrangement in Fig. 3 is substantially the same, except that here in place of a separate controlling-magnet the regulating-coil itself maybe employed for this purpose, a short laminated core 5 being inserted in one end to act upon the resistance-varying armatu re. The carbon contacts are so placed that upon a decrease of current the armature is retracted and the conductivity of the shunt increased.

sponsive to the lamp-current to control the same.

2. An arc-lamp having a variable resistance in a by-pass around the regulating-coil, and a magnet of shorter time constant than said regulating-coil governed by the arc to divert more current through the by-pass as the arc lengthens.

3. An arc-lamp having a variable resistance in a by-pass around the regulating-magnet, and a magnet of shorter time constant than said regulating-magnet responsive to the lamp-current and governing the resistance.

4. An arc-lamp having a variable contact in a by-pass around the regulating-magnet, an armature governing the contact, a stiff spring on the armature, and a magnet of shorter time constant than the regulatingmagnet controlling the armature.

5. An arc-lamp having a shunt around its regulating-coil, a magnet of shorter time constant than the regulating-coil governed by the lamp-current, an armature controlled thereby for varying the resistance of the shunt, and a dash-pot to steady the movement of the armature.

6. An arc-lamp having a shunt around its regulating-magnet, a magnet of shorter time constant than the regulating-magnet governed by the lamp -current, an armature controlled thereby, and a variable contact carried by said armature for decreasing the resistance of the shunt with decrease of lamp-current, the armature and its attached parts being of small inertia to permit quick action.

7. An arc-lamp provided with a regulatingmagnet, an auxiliary circuit for varying its magnetization, and a control-magnet to graduate the resistance of said auxiliary circuit, said control-magnet having a low time constant relatively to the regulatingmagnet and provided with an armature biased bya stiff retractile spring.

In Witness whereof I have hereunto set my hand this 21st day of August, 1901.

EDWIN W. RICE, JR.

Witnesses:

M. H. EMERSON, O. L. HAYNES. 

